Vacuum tube



Dec. 18, 192-3. 11,478,?2 H. J. VAN DER BIJL VACUUM TUBE Filed March 20, 1918 Patented Dec. 18, 1923.

NIT ED STATES "HENDRIK J. VAN DER .BI J L, OF NEW YORK, N. Y., ASSIGNOR TO W ESTERN ELECTRIC COM- PANY, INCORPORATED, OF NEW! YORK, N. Y., A CORPORATION OF NEW YORK.-

Application filed March 20, 1918. Serial No. 223,605.

To all whom, it may concern:

Be it known that I. HENnmK J. VAN DER BIJL, a subject of the King of Great Britain, residing at New York. in the county of New York and State of New York, have invented certain new and useful Improvements in vacuum Tubes, of which the following is a full, clear, concise, and exact description.

This invention relates to vacuum tubes and more particularly it relates to tubes of the audion type, an object being to increase the working range of such tubes.

In a vacuum tube of theaudion type there are usually enclosed a cathode or filament, an an0de,'usually in the form of a plate, and a third electrode. usually called a grid. The usual method of employing such a tube is to vary the potential of the grid in accordance with the currents to be amplified, whereby the space current flowing between the cathode and anode will be varied accordingly, which variations being in amplified form, may be'impressed on the desired receiving apparatus.

The amount of current flowing between the cathode and anode depends in general .upon the rate the electrons are being emitted from the cathode and the value of the potential applied between the cathode and anode. For high-power output tubes, it is advantageous of course to make the space current as large as possible in value in order to get a high-powered output of the tube, but it "has been found that the amount of space current is limited in value by the fact that the plate electrode for large currents buckles under the heat of the electron bombardment from the cathode, thereby distorting the space relation of the electrodes and in some cases destroying the action of the tube by the plate coming in contact with another one of the electrodes. It has also been found preferable to reinforce the grid or control electrode, since the grid becomes heated to a considerable extent during the process of evacuation of the tube when it is being manufactured.

In accordance with this invention this buckling of the anode and the grid for large currents is prevented by providing strengthening means such as ridges in the two electrodes, whereby a very much larger working range of the tube is assured.

For the better understanding of this in vention, reference is made to the following detailed description taken in connection with the accompanying drawings in which Fig. 1' represents a vacuum tube embodying this invention, and Fig. 2 shows how such a tube may be applied for the repeating or amplifying of alternating currents.

Referring to Fig. 1, 5 is a vacuum tube having a double plate anode 6, a cathode 7 and a double grid 8. These electrodes are supported by suitable supporting wiresattached to the glass arbor 10, which in turn is attached to the press 11 of the tube at a point preferably below the flattened por tion 12. 15 to 18 inclusive are leading-in Wires for the various electrodes.

In order to strengthen the plate 6, each is provided with ridges or turned-up .portions 21 which prevent the plates from buckling when heated, for instance to yellow heat, by the electron bombardment from the cathode. The grid 8 also. is provided with ridges 24 to prevent it from warping. These ridges may consist of the turned-up edges of the vertical strips of the grid, which edges may be turned outwardly toward the plate as shown, or they may be turned inwardly towards the filament in any suitable manner. The tube will therefore have a higher power output than it would otherwise have, so that when the tube 5 is connected up in an electric system such as the one shown in Fig. 2, the currents repeated from line 30 to line 32 will be of far greater intensity than it would be possible to have with the strengthening means omitted.

It is obvious that the strengthening means may be variously modified from the particular type above described without departing in any wise from the spirit of this invention, as defined in the appended claims.

What is claimed is: I

1. A vacuum tube comprising an anode, a cathode, and a grid, means for heating said electrodes, ridges on said anode for reinforcing said anode to maintain the spaced relation of said anode and another of said electrodes when said electrodes are subject to heat, and ridges on said grid for re-inforcing said grid to maintain the spaced relation with respect to the remaining electrodes, said ridges on said grid being so positioned as to ofier substantially no obstruction to the passage of electrons from said cathode to said anode.

2. A control electrode for a vacuum tube are also containing an anode and a cathode, said control electrode comprising parallel members angular in cross section, and a plurality of cross bars extending therebetween. 3. An electron discharge device comprising an ,anode, a cathode, said anode having a substantially plane surface in adefinite space relation with respect to said cathode, and means comprisingridges on said anode for re-inforcing said anode to maintain'the desired space relation of the reinforced anode and said cathode and to prevent said anode from buckling when said electrodes are subjected to heat 4. A vacuum tube comprising an anode, a cathode, means for heating said electrodes, and reinforcing means for said anode for maintaining the desired space relation of said anode and said cathode when'said electrodes are subjected to heat, said means comprising on a plurality of the sides of said anode, a portion of said anode bent substantially at right angles to the main body portion of said anode.

In witness whereof, I hereunto subscribe my name this 9th day of March, A; D., 1918.

HENDRIK J. VAN mm BIJL. 

